Method of and apparatus for extracting bitumen



Oct. 14, 1969 a. H. MILLER 3,472,553

METHOD OF AND APPARATUS FOR EXTRACTING BITUMEN Filed May 3, 1967 3 Sheets-Sheet 1 16 I 12 I 1 I N I /l N I I I O 0 o I I o a o a l l' 0 o z "E a 0 o o we 7 ,1 a

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O o c O o b 0 (3 0 a a o 0 O a IN VENTOR ATTORNEY Och 1969' a. H. MILLER 3,472,553

METHOD OF AND APPARATUS FOR EXTRACTING BITUMEN Filed May 5 1967 3 Sheets-Sheet r 4 I l 4 26 i 26 O lbc v" o 0 I9 IO 22 o a a 0 a 0 0 23 j a v 24 o O 0 0 o 0 c, O O 0 0 o o a 0 O o 0 o o o a Bruno H. Mi/ler ATTORNEY INVENTOR Oct 14, 1969 METHOD OF AND APPARATUS FOR EXTRACTING BITUMEN Filed May 5, 1567 B. H. MILLER 3 Sheets-Sheet. 3

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I NVEN TOR United, States Patent 3,472,553 METHOD OF AND APPARATUS FOR EXTRACTING BITUMEN Bruno H. Miller, Cravens Building, Oklahoma City, Okla. 73102 Filed May 3, 1967, Ser. No. 635,787 Int. Cl. E02l 41/00 US. Cl. 299-5 15 Claims ABSTRACT OF THE DISCLOSURE Extraction of bitumen in situ from subterranean tar sands, shales and similar formations, where a hole is drilled to the top of the formation, is lined with a casing, and a sump is drilled in the formation below the casing. A solvent for bitumen is introduced into the sump, and an expandable rotary agitating tool is inserted through the casing into the sump in the formation. The tool consists of a flexible flail carried by a rotatable shaft and provided with a beater member at its outer end, which contacts the walls of the sump to break up the formation. Rotation of the tool also sets up a turbulent force which hurls the solvent against the sump walls to aid in dislodging bitumen-bearing particles and to dis-solve the bitumen therefrom. The solvent and dissolved bitumen are pumped to the surface, while the bitumen-denuded particles remain in the sump. In a modified arrangement, the agitating tool operates on bitumen bearing material placed in a receptacle after being brought to the surface in a conventional manner.

This invention relates to new and useful improvements in the art of extracting bitumen from tar sands, shales and similar bitumen bearing subterranean formations, and in particular the invention concerns itself with such extraction of bitumen in situ.

Where bitumen is found in tar sands, or the like, each grain of sand is encased in a film of an oily, tarry substance which is inert and non-volatile, and which must be removed from each grain of sand before the bitumen can be utilized. The bitumen adheres tightly to each grain of sand and each grain in turn adheres to others around it, thus making a cohesive and almost impenetrable mass which, in a subterranean formation, is very difficult to be worked in situ. Thus, in conventional practice it was customary to either bring up the bitumen bearing material to the surface for treatment, or, where conditions permitted, to expose the formation by removal of the overburden. In either event, the conventional procedure could not be practiced economically and the usual treatment of merely subjecting the bitumen bearing material, either in situ or on the surface, to the action of a bitumen solvent did not produce fully effective results, inasmuch as the solvent cannot penetrate the formation to any substantial extent and only a very thin layer is dissolved and dislodged from the formation, so that endless applications of the solvent must be made.

It is, therefore, the principal object of this invention to eliminate the disadvantage above outlined and to facilitate highly expeditious and economical extraction of bitumen in situ from subterranean formations. This object is attained by providing a method and apparatus whereby individual grains of tar sands or layers of shale may be dislodged from the formation and separated from each "ice other so that the bitumen film encasing the same may be readily reached and dissolved, whereupon the solvent and the dissolved bitumen may be pumped to the surface while leaving the bitumen-denuded particles in the formation.

As such, the invention utilizes a casing-lined hole drilled from the ground surface to the top of a bitumen bearing formation which itself is drilled to form a cavity or a sump. A rotatable shaft is inserted through the casing and carries a rotary agitating tool in the form of an elongated flexible element or flail, secured at one end thereof to the shaft and provided at its other end with a beater member. When the shaft is stationary, the agitating tool or flail simply hangs alongside the shaft, so that it may be passed through the casing into the sump in the formation. A suitable solvent for bitumen is intro duced through the casing into the sump, and when the shaft is rotated, the agitating tool expands or flails out far beyond the diameter of the casing above it, and the beater member of the tool contatcs the walls of the sump so as to dislodge and break down the formation into individual bitumen-bearing particles. Moreover, rotation of the tool sets up a centrifugal turbulent force upon the solvent which enables the solvent to efliectively reach the dislodged particles for releasing them from each other and for dissolving their bitumenous coating, whereupon the solvent and the dissolved bitumen may be pumped out of the sump while leaving the bitumen-denuded particles behind.

An important feature of the invention resides in the arrangement and action of the flail-like agitating tool which serves not only to break down the formation but also to set up a turbulent force by which the solvent is hurled against the walls of the sump to aid in dislodging bitumen-bearing particles and to dissolve their bituminous coating. Although this arrangement is ideally suited for working subterranean formations in situ, it may also be effectively employed, as in a tank or some other receptacle, for treating bitumen-bearing material which has been brought to the surface in the conventional manner.

Another important feature of the invention associated with the flail-like agitating tool is the ability of the tool to be passed through a casing of a relatively small diameter, yet to have a much larger effective or working diameter in the formation below the casing, when the tool is expanded or fiailed out by rotation of its shaft. By adding additional flail sections in series the effective working diameter of the flail-like agitating tool can be increased an indefinite number of times within practical limits.

Another important feature ofthe invention resides in the proivsion of upwardly acting, rotary auger-like means on the shaft below the agitating tool, such auger-like means extending into the formation at the bottom of the sump therein so as to discourage seepage of solvent and dissolved bitumen downwardly from the sump.

Another feature of the invention resides in the step of rotating an expandable agitating tool in a sump being formed in a bitumen bearing formation and simultaneously withdrawing a solvent and dissolved bitumen from the sump in order to reduce the seepage of the solvent into the unworked formation.

Another important feature of the invention resides in the provision of means whereby the solvent and dissolved bitumen may be conveyed, as by pumping, from the sump a in the formation to the surface through the shaft of the agitating tool, so that the extracting operation may take place in a continuous manner and without the necessity of interrupting rotation of the tool, such as would be necessary if the solvent and dissolved bitumen were pumped out through a conduit separate from the shaft.

With the foregoing more important objects and features in view and such other objects and features as may become apparent as this specification proceeds, the invention will be understood from the following description taken in conjunction with the accompanying drawings, wherein like characters of reference are used to designate like parts, and wherein:

FIGURE 1 is a fragmentary vertical sectional view showing the apparatus of the invention in situ;

FIGURE 2 is an enlarged, fragmentary cross-sectional detail, taken substantially in the plane of the line 2-2 in FIG. 1;

FIGURE 3 is a view, similar to that shown in FIG. 1, but illustrating a modified embodiment of the apparatus;

FIGURE 4 is an enlarged, fragmentary cross-sectional detail, taken substantially in the plane of the line 44 in FIG. 3; and

FIGURE 5 is a vertical sectional view showing a modified arrangement of the apparatus for treating bitumen bearing material in a receptacle or tank.

Referring now to the accompanying drawings in detail, more particularly to FIG. 1, the reference numeral designates a subterranean formation of tar sands, shales or other similar bitumen bearing material, the formation 10 underlying an overburden 11 and the surface of the ground being indicated at 12.

In accordance with the invention, the extraction of bitumen from the formation or structure 10 involves the drilling of a hole 13 downwardly from the ground surface 12 to the top of the formation, the hole being lined with a casing 14 to prevent cave in. The formation 10 itself is then drilled through the casing 14- so as to form a cavity or sump in the formation, as indicated by the dotted lines 15.

A rotatable shaft 16 is inserted through the casing 14 into the sump in the formation, the portion of the shaft which enters the sump being equipped with an expandable, rotary agitating tool designated generally as 19. The tool 19 comprises an elongated, flexible element or flail 20, such as a length of chain, for example, one end of which is secured to a collar 21 fastened to the shaft 16, while its other end is provided with a beater member 22. Conveniently, the latter may assume the form of a metal ball or sphere, with spike-like projections on its surface.

The length of the flail can be increased to an indefinite length by the gradual addition of more links or sections as the cavity in 10 becomes extended from the hole 13 by the disintegration of its outer walls. It is to be understood that at the beginning of the operation a short length of chain 20 would be more effective than a long length of chain, but as the Walls of the cavity are extended outwardly it would be necessary to lengthen the chain 20 or the tool would lose its disintegrating function and would whirl around in the cavity, merely agitating the solution already formed. Sections may be added to the flail 20 by stopping the rotation of the tool 19 and pulling it to the surface, where additional chain sections may be added. The tool will then be reinserted into the sump and rotation thereof will be begun once more.

When the shaft 16 is stationary, the agitating tool 19 simply hangs alongside the shaft and, as such, the shaft with the tool may be conveniently passed through the casing 14 and into the sump 15 in the formation 10. However, when the shaft is rotated, the tool 19 is flailed out or expanded by centrifugal force and contact of the beater member 22 with the walls of the sump 15 breaks down or disintegrates the formation so that its bitumen-bearing particles are dislodged. Of course, as the action of the tool is continued, the sump 15 becomes progressively enlarged until it attains a maximum transverse dimension corresponding to the effective operating diameter of the beater member 22 at the end of the chain 20. In addition to "breaking down the formation, the agitating tool also sets up a centrifugal turbulent force to act upon a suitable solvent for bitumen which has been introduced into the sump through the casing 14, either prior to or concurrently with energization of the agitating tool. This turbulent force causes the solvent to be hurled against the walls of the sump to aid in dislodging the bitumenbearing particles from the sump walls and also in separating the particles from each other, so that the individual particles are made readily accessible to the solvent for effective dissolving of their bituminous coating.

The shaft 16 preferably is hollow and is provided below the collar 21 with a set of openings or apertures 23 so that the solvent and dissolved bitumen may be conveyed, as by pumping, from the sump and upwardly through the shaft to above ground. This permits the bitumen extracting operation to be carried on continually without interruption of rotation of the agitating tool, such as would otherwise be required if the solvent and dissolved bitumen were pumped out through a conduit separate from the shaft.

It will be also appreciated that the shaft 16 may be slid downwardly in the casing 14 as the extracting operation progresses, thus correspondingly lowering the agitating tool 19 and deepening the sump until the bottom of the bitumen bearing formation is reached.

In order to discourage downward seepage of the solvent and dissolved bitumen in the sump, a rotary auger or screw 24 is secured to the lower end of the shaft 16 below the agitating tool 19. The auger 24 extends into the formation 10 at the bottom of the sump and the shaft and anger are rotated in such directions that the auger feeds upwardly into the sump, to discourage downward seepage of solvent and dissolved bitumen, as already noted.

The shaft 16 may be rotated by any suitable aboveground means, as for example a conventional turntable 17 which also allows for the shaft to be slid downwardly as required.

However, a somewhat modified embodiment of the invention is shown in FIG. 3, wherein the shaft 16a is rotated by a motor, such as an electric motor 25, positioned within the casing 14. The shaft 16a in effect may be regarded as an extension of the armature of the motor 25, since the motor surrounds the shaft in a coaxial manner. In order to assure rotation of the shaft 16a, means are provided for preventing rotation of the motor housing, these means consisting of a pair of lugs 26 which project to opposite sides from the motor housing and slidably engage a pair of vertical guide bars 27 provided inside the casing 14, as will be clearly apparent from FIG. 4. Thus the motor housing is prevented from rotating, but the motor is still free to slide, along with the shaft 16a, longitudinally in the casing 14, as required. Current is supplied to the motor 25 by a suitable conductor 28, as will be apparent.

Manifestly, if solved and dissolved bitumen in the sump is to be pumped to the surface through the shaft 16a, the shaft must be hollow and provided with the aforementioned openings 23.

While the invention is primarily concerned with extraction of bitumen in situ from subterranean strata, its teachings may also be employed in treating bitumen-bearing material after it has been removed from below ground and brought to the surface in a conventional manner. This modified arrangement is illustrated in FIG. 5 wherein the shaft 16, equipped with the agitating tool 19 and with a suitable drive member 18, extends into a suitable tank or receptacle 29, in which the bitumen-bearing material 10a is placed. A sump may be preformed in the material for reception of the agitating tool, or the material may simply be positioned in the tank around the tool so that a sump is. formed in the material by the tool rotation. In any event, the extraction procedure may be effected in the same manner as already described in connection with subterranean extraction in situ, and the solvent introduced into the material in the tank may be pumped out along with the dissolved bitumen through the shaft 16, as already explained. Of course, unless the tank 29 were of substantial depth, it would not be necessary to employ the auger-like means 24 to discourage seepage of solvent and dissolved bitumen downwardly from the sump.

While in the foregoing there have been described and shown the preferred embodiments of the invention, various modifications may become apparent to those skilled in the art to which the invention relates. Accordingly, it is not desired to limit the invention to this disclosure, and various modifications and equivalents may be resorted to, falling within the spirit and scope of the invention as claimed.

What is claimed as new is:

1. A method of extracting bitumen in situ from subterranean tar sands, shales and similar bitumen bearing formations, said method comprising the steps of drilling a hole downwardly from the ground surface to the top of a bitumen bearing formation, casing the drilled hole, drilling into the formation to produce a sump therein from which bitumen is to be extracted, inserting a slender expandable rotary agitating tool through the drilled hole into the sump, introducing a solvent for bitumen into the sump, rotating the agitating tool so as to expand the same into contact with the wall of the sump and to set up a centrifugal turbulent force upon the solvent whereby to hurl the solvent against the wall of the sump and aid in dislodging bitumen-bearing particles from the sump wall, and pumping the solvent and dissolved bitumen from the sump to the ground sunface while leaving bitumen-denuded particles in the sump.

2. The method as defined in claim 1 together with the step of inserting upwardly acting rotary auger-like means into the formation at the bottom of the sump whereby to discourage seepage of solvent and dissolved bitumen downwardly from the sump into the formation.

3. The method set forth in claim 1 wherein the expandable rotary agitating tool includes an elongated flexible element connected at one end to the tool shaft and having a free end provided with a toothed disintegrator element for breaking down the walls of the sump.

4. A method of extracting bitumen from tar sands, shales and similar bitumen bearing material, said method comprising the steps of placing the bitumen bearing material in a receptacle having a rotary expandable agitating tool therein, introducing a solvent for bitumen into the material in the receptacle, rotating the agitating tool so as to expand the same to form a sump in the bitumen bearing material and to set up a centrifugal turbulent force upon the solvent whereby to hurl the solvent against the wall of the sump and aid in dislodging bitumen-bearing particles from the sump wall, and pumping out the solvent and dissolved bitumen from the sump while leaving bitumen-denuded particles therein.

5. An apparatus for extracting bitumen in situ from subterranean tar sands, shales and similar bitumen bearing formations, said apparatus comprising in combination a casing adapted to be inserted in a hole drilled downwardly from ground surface into a bitumen bearing formation, a rotatable shaft extending longitudinally through and projecting below said casing, a slender expandable rotary agitating tool carried by said shaft below said casing comprising an elongated flexible flail-like element secured at one end to said shaft and normally depending therefrom by gravity, said casing serving for introduction of a solvent for bitumen into the bitumen hearing formation, means for rotating said shaft with said agitating tool so as to expand the latter into contact with the formation and to set up a centrifugal turbulent force for hurling solvent against the formation whereby to dislodge bitumen-bearing particles therefrom, and means for conveying solvent and dissolved bitumen upwardly through said shaft to the ground surface.

6. The apparatus as defined in claim 5 together with upwardly acting rotary auger-like means carried by said shaft below said agitating tool for discouraging downward seepage of solvent and dissolved bitumen.

7. The apparatus as defined in claim 5 wherein said means for rotating said shaft are disposed above said casing.

8. The apparatus as defined in claim 5 wherein said means for rotating said shaft comprise a motor coaxially surrounding the shaft in said casing, said motor including a housing slidably but non-rotatably disposed in the casing.

9. In an apparatus for extracting bitumen from tar sands, shales and similar bitumen bearing material, the combination of a rotary shaft, an agitating tool com prising an elongated flexible element secured at one end thereof to said shaft, and a heater member provided at the other end of said flexible element, and means for rotating said shaft whereby to bring said heater member in contact with bitumen bearing material treated by a bitumen solvent and whereby to set up a centrifugal turbulent force for hurling the solvent against the material to dislodge bitumen-bearing particles therefrom.

10. The apparatus as defined in claim 9 together with a receptacle for the bitumen bearing material and solvent, said agitating tool being disposed in said receptacle.

11. A method of extracting bitumen from tar sands, shales and similar bitumen bearing material, said method comprising the steps of introducing a solvent for bitumen into the material from which bitumen is to be extracted, rotating an agitating tool in the material and within the solvent so that the latter is broken down into bitumenbearing particles and so that a centrifugal turbulent force is set up upon the solvent to assist in dislodging of the particles for access by the solvent to the bitumen constituent thereof, and removing the solvent and dissolved bitumen from the material while leaving bitumen-denuded particles therein.

12. The method set forth in claim 11 wherein the step of pumping the solvent and dissolved bitumen from the sump to the ground surface is performed simultaneously with the rotating of the agitating tool in order to reduce the seepage of the solvent into the unworked formation.

13. The method set forth in claim 11 together with the steps of continuing the steps of rotating the agitating tool and pumping the solvent and dissolved bitumen until the walls of the sump have been extended radially outwardly by the rotary disintegrating action of the expandable rotary agitating tool beyond the expanded length thereof, stopping the rotation of the agitating tool, withdrawing the tool to the surface of the ground, adding an additional length to the expandable agitating tool to increase its effective length, reinserting the expandable agitating tool into the sump and repeating the steps of rotating the agitating tool and pumping the solvent and dissolved bitumen from the sump to the ground.

14. An apparatus for extracting bitumen material in situ from subterranean tar sands and the like comprising a slender expandable tool adapted when unexpanded to be lowered through a restricted opening into a subterranean cavity of tar sands or the like, said tool comprising a rotatable shaft having an elongated flexible surface eroding element or flail carried thereby and normally extending downwardly by gravity when the tool is stationary, but being adapted to extend outwardly by centrifugal force into eroding contact with the walls of the cavity when the tool is rotated, and means for rotating said tool.

15. An apparatus as defined in claim 3 wherein the shaft is hollow and the cavity contains a solvent for the bitumen material within the cavity, and means for pumpthrough said hollow shaft.

7 8 ing said solvent and extracted material from said cavity 1,607,586 11/1926 Claytor 299-5 2,251,916 8/1941 CIOSs 2995 References Cited FOREIGN PATENTS UNITED STATES PATENTS 5 286,814 2/1965 Netherlands. 11/ 1918 Otto 175- 63 X ERNEST R. PURSER, Primary Examiner 9/1923 Hogue 175263 12/1923 Wolever 17564 X US. Cl. X.R. 10/ 1925 De Fontaine 175263 10 175-64, 263; 20s 11-,259-111 

